Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran 14174, Iran.
Bioresour Technol. 2011 Jan;102(2):1808-14. doi: 10.1016/j.biortech.2010.09.043. Epub 2010 Sep 17.
An extracellular laccase-producing ascomycete was isolated from soil and identified as Paraconiothyrium variabile using rDNA sequence analysis. Typical laccase substrates including 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS), 2,6-dimethoxyphenol (DMP), and guaiacol were oxidized by the purified enzyme (designated as PvL). The molecular mass of PvL was 84 kDa and it showed a pI value of 4.2. The enzyme acted optimally at pH 4.8 and exhibited an optimum temperature of 50 °C. Using ABTS, PvL represented Km and Vmax of 203 μM and 40 μmol min(-1) mg(-1), respectively. After 24 h incubation at pH 4.8 and 4 °C, 80% of the initial activity of PvL remained. The enzyme was inhibited by Fe2+, Hg2+, and Mn2+, but induced by Cu2+. EDTA (10 mM), 1,4-dithiothreitol (DTT) (0.1 mM), and NaN3 (10 mM) were found to completely inhibit PvL. Sixty-eight percent of Malachite green was decolorized by 4 U/mL of PvL after 15 min incubation at 30 °C.
从土壤中分离到一株产细胞外漆酶的子囊菌，通过 rDNA 序列分析鉴定为变色栓菌（Paraconiothyrium variabile）。该酶能有效氧化典型的漆酶底物 2,2'-联氮-双（3-乙基苯并噻唑啉-6-磺酸）（ABTS）、2,6-二甲氧基苯酚（DMP）和愈创木酚。纯化后的漆酶（命名为 PvL）的分子量为 84 kDa，等电点为 4.2。该酶最适 pH 值为 4.8，最适温度为 50°C。以 ABTS 为底物时，PvL 的 Km 和 Vmax 值分别为 203 μM 和 40 μmol min(-1) mg(-1)。在 pH 4.8 和 4°C 下孵育 24 h 后，PvL 的初始活性仍保留 80%。该酶被 Fe2+、Hg2+和 Mn2+抑制，但被 Cu2+诱导。EDTA（10 mM）、1,4-二硫苏糖醇（DTT）（0.1 mM）和叠氮化钠（NaN3）（10 mM）完全抑制了 PvL。在 30°C 下孵育 15 min 后，4 U/mL 的 PvL 能使 68%的孔雀石绿脱色。
